This invention relates generally to the quantitative measurement of proteins in mixtures, especially when only small amounts of material are available.
In view of the current rapid expansion of knowledge concerning the role of proteins in health and disease, there is an increasing need for a general, rapid and relatively economical quantitative method for protein analysis of such fluids as serum, spinal fluid, tissue extracts and the like.
The proteins occurring in such fluids are frequently identified by immunochemical procedures which depend upon precipitation of each protein by an antibody specific to the particular protein. The production of such specific antibodies is stimulated when foreign proteins (antigens) are introduced into a living body. Antisera can be prepared, containing known mixtures of such antibodies. By reacting a protein sample in vitro with such an antiserum and observing the resulting precipitation, or lack of precipitation, useful information may be obtained as to the types of proteins in the sample.
Previous attempts to obtain quantitative results with immunochemical procedures have generally employed processes which are not well suited for the present purpose. In particular, many such processes have the serious disadvantage that they require the use of antisera that are rigorously immunochemically specific for the single protein of which the concentration is to be determined. If the antiserum contains even small amounts of contaminating antibodies against other proteins that are present in the mixture, vastly erroneous results may be obtained. Although it is ordinarily possible to obtain immunochemically specific antisera which react with only a selected single protein and do not cross react with other proteins, this requires relatively complex and expensive procedures which are difficult to carry out on a routine basis and are expensive.